A complementary metal oxide semiconductor (CMOS) image sensor is paid attention to as image sensor for shooting images at the request of downsizing and the like.
A CMOS image sensor has an AD converter for performing analog to digital (AD) conversion on an analog electric signal output by a pixel for performing photoelectric conversion. The AD converter has a comparator and a counter, and compares a predetermined reference signal with an electric signal output by a pixel thereby to AD-convert the electric signal.
A plurality of AD converters, each of which corresponds to each column or the like of pixels, for example, are arranged in line, and the electric signals output by one row of pixels are AD-converted in parallel (at the same time) in the CMOS image sensor.
In a case where a plurality of AD converters are arranged in line, a deterioration in crosstalk characteristics between a comparator configuring an AD converter and a comparator of its adjacent AD converter may cause a deterioration in image quality of an image obtained by the CMOS image sensor.
There is thus proposed a CMOS image sensor in which a first transistor and a second transistor, which are a pair of transistors configuring a differential pair of an input stage of a comparator, are divided into an equal number of divided transistors, respectively, and a plurality of divided transistors configuring a predetermined column of comparators and a plurality of divided transistors configuring a column of comparators adjacent to the predetermined column are arranged in different arrangement patterns thereby improving crosstalk characteristics without any adverse effect (see Patent Document 1, for example).